Heat oven to 350°F.
In a large bowl, beat the butter and sugars together with an electric mixer until very light and fluffy, about 5 minutes. Beat in the egg and vanilla, scraping down the bowl as needed. Beat in the salt and baking soda, then the flour on a low speed until just mixed. Add the chocolate chunks, along with all the tiny bits.
Scoop large balls of dough onto a parchment-lined baking sheet and if you like, sprinkle each with a pinch of sea salt. Bake for 12-14 minutes, until golden but still soft and gooey in the middle.
Makes about 2 dozen cookies.